I didn't know that mental conditions are this visible

[Plazma Inferno!]

I guessed there is different level of activity in different areas of brain, but I didn't know that PET could actually show this.

So, is this accurate? Is there some kind of relation between brain activity, blood flow and warmer/colder areas on the images? Could someone please explain?

 

[Billy T]

I guessed there is different level of activity in different areas of brain, but I didn't know that PET could actually show this....
So, is this accurate? Is there some kind of relation between brain activity, blood flow and warmer/colder areas on the images? Could someone please explain?

More active brain cell in some region dump more CO2 into the local blood veins, making it more acid. The brain's veins respond to more acidity by expanding (no others do this AFAIK). Thus with lower resistance to flow, the same blood pressure moves more blood (and O2) thru that part of the brain and in a self stabalizing control loop the greater flow brings down the CO2 levels some.

I doubt the local cooling is significant, but it might be; probably the PET scan is responding to the changing local blood chemistry, not thermal differences, but again I don't know

 

[Plazma Inferno!]

Thanks for an explanation.